Hyperpituitarism is the excessive production of growth hormone, which continues to be produced well into adulthood. In adults it is involved in regulatory functions in the body, but since the growth plates are closed, excessive levels cause abnormal growth of hands, feet, and internal organs. In children, excess growth hormone causes increased height known as Gigantism.
Similar conditions include hyperprolactinemia, hypothyroidism, sleep apnea and carpal tunnel syndrome.
Since pituitary tumors (usually benign) are the most common cause of this condition, other areas controlled by the pituitary are often affected, such as Prolactin and thyroid hormones. Another cause is carcinoid tumors.
Symptoms of excess growth hormone include:
Diagnosis is made through examination (large, "doughy" hands; large feet; large face; enlarged jaw; tongue problems; big forehead; darkened skin in armpits; widely spaced teeth; oily, tough skin; skin pigmentation changes – darker or lighter; excessive hair growth in females; high blood pressure; goiter (enlarged thyroid); kyphosis or loss of disc spaces of the spine; osteoporosis; osteoarthritis), through laboratory findings (growth hormone level is high, even when patient receives glucose load; diabetes occurs in 30% of cases; elevated IGF-1; elevated prolactin level; elevated liver function; elevated blood urea nitrogen; elevated phosphorus; decreased free thyroxine; elevated thyroid stimulating hormone) and through imaging (MRI shows pituitary tumor).
Treatment can consist of pituitary microsurgery to remove tumor; pituitary radiation if surgery fails; gamma knife radiation treatment (a special type of focused radiation); bromocriptine (helps decrease growth hormone in some patients); octreotide (partially shrinks pituitary tumors).